Method and apparatus for providing intra-pericardial access

ABSTRACT

A method and apparatus for accessing the pericardial space which provides for stable short term or long term placement of a delivery catheter or cannula having its distal most end located in the pericardial space. The catheter or cannula may be introduced into the pericardial space either transvenously through the wall of a heart chamber or transthoracically by penetrating the chest wall and the pericardium. Some embodiments are provided with a mechanism for stabilizing the distal end of the catheter or cannula, which mechanism may employ an extensible elastic, generally tubular member located at the distal end of the catheter or cannula. The device may be provided with a mechanism for extending the tubular member longitudinally, causing its diameter to diminish substantially. The tubular member may be passed through the wall of the heart or the pericardium in its extended configuration and thereafter, the distal-most portion of the tubular member may be moved proximally, causing its diameter enlarge, anchoring the distal end of the catheter or cannula to the pericardium or to the wall of a heart chamber. In these embodiments, the device is preferably provided with a shoulder or flange located proximal to the extendible tubular member, for location on the opposite side of the heart wall or pericardium from the distal end of the catheter or cannula.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to diagnostic and therapeuticdevices for insertion into a patient's body, and more particularly todevices for access to and delivery of treatment in the pericardialspace.

[0002] Access to the pericardial space is desirable in order to providea variety of cardiac therapies, including delivery of drugs or geneticagents, placement of electrical leads for pacing, cardioversion,defibrillation or EGM monitoring, removal of pericardial fluid fordiagnostic analysis, or other purposes. A variety of mechanisms havebeen developed for accessing the pericardial space, ranging from asimple puncture by means of a large bore needle to intricate catheter orcannula based systems provided with sealing and anchoring mechanisms.Access to the pericardial space may be accomplished from either outsidethe body, by piercing the pericardium or from inside the heart, bypiercing the wall of a heart chamber.

[0003] Prior art mechanisms adapted to access the pericardial space bypiercing the heart chamber include U.S. Pat. No. 5,797,870 issued toMarch et al, which discloses use of a transvenous catheter provided witha hollow helical needle to pierce the wall of a heart chamber.Alternatively access to the pericardial space may also be accomplishedby means of a transvenous catheter which pierces the wall of a heartchamber and allows passage of a lead therethrough is disclosed in U.S.Pat. No. 4,946,457 issued to Elliot, U.S. Pat. No. 4,991,578 issued toCohen. and U.S. Pat. No. 5,330,496 issued to Alferness. Particularly inthe context of access to the pericardial space via the right atrium, ithas been proposed that the transvenous catheter pierce the right atrialwall, as in U.S. Pat. No. 4,946,457 issued to Elliot or that thecatheter pierce the right atrial appendage as in U.S. Pat. No. 5,269,326issued to Verrier. Access to the pericardial space from the exterior ofthe body, accomplished by passing a cannula or catheter type devicethrough the chest wall and thereafter passing the cannula or catheterthrough the pericardium into the pericardial space is disclosed in U.S.Pat. No. 5,827,216 issued to Igo, U.S. Pat. No. 5,336,252 issued toCohen and PCT Patent Application WO/99/13936, by Schmidt.

SUMMARY OF THE INVENTION

[0004] The present invention is directed toward providing a mechanismfor accessing the pericardial space which provides for stable short termor long term placement of a delivery catheter or cannula having itsdistal most end located in the pericardial space. The catheter orcannula may be introduced into the pericardial space eithertransvenously through the wall of a heart chamber or transthoracicallyby penetrating the chest wall and the pericardium.

[0005] In particular, some embodiments of devices according to thepresent invention are provided with a mechanism for stabilizing thedistal end of the catheter or cannula. In a first embodiment of theinvention, the mechanism for stabilizing the distal portion of thecatheter or cannula comprises an extensible elastic, generally tubularmember located at the distal end of the catheter or cannula. The deviceis provided with a mechanism for extending the tubular memberlongitudinally, causing its diameter to diminish substantially. Thetubular member is passed through the wall of the heart or thepericardium in its extended configuration and thereafter, the distalmost portion of the tubular member is moved proximally, causing itsdiameter enlarge, anchoring the distal end of the catheter or cannula tothe pericardium or to the wall of a heart chamber. In these embodiments,the device is preferably provided with a shoulder or flange locatedproximal to the extendible tubular member, for location on the oppositeside of the heart wall or pericardium from the distal end of thecatheter or cannula.

[0006] In other embodiments of the present invention, the catheter orcannula takes the form of two nested tubular members, each provided withan extensible flange. The innermost of the two tubular members isprovided with one or more radially extending protrusions or recesses,which engage with one or more corresponding protrusions or recesseslocated on the interior surface of the outer tubular member. Preferably,a series of outwardly directed protrusions on the inner tubular memberand a series of inwardly directed protrusions the outer tubular memberare provided, together defining multiple detent points for stabilizingthe longitudinal position of the inner and outer tubular membersrelative to one another. More preferably, the protrusions andindentations of the tubular members extend around less than the entirecircumference of the tubular members and are arranged so that in a firstconfiguration, the tubular members may be slid longitudinally withrespect to one another without interference between the protrusions onthe inner and outer tubular members and in a second configuration theprotrusions on the tubular members are interlocked to prevent relativelongitudinal movement. In use, the catheter or cannula is employed byfirst passing the distal tip of the inner tubular member through thepericardial wall or the wall of a heart chamber such that the flangelocated thereon is located inside the pericardial space. The outertubular member is then moved distally relative to the new tubular memberto a point where the inner and outer flanges are located on either sideof the pericardium or the heart wall, and the interlocking protrusionson the inner and outer catheter are thereafter employed to stabilize thecatheter by preventing further relative longitudinal movements of theinner and outer tubular members.

[0007] In addition to the delivery of drugs, extraction of pericardialfluids, and location of medical electrical leads typically as typicallyaccomplished by means of pericardial access to devices, the devicesaccording to the present invention may also be employed as part of asystem for accomplishing cardiac ablation. In this context, afterstabilization of the catheter's or cannula's distal end in thepericardial space, an ablation catheter is passed through to thecatheter or cannula into the pericardial space, is located at a desiredlocation adjacent the epicardium of the heart and is thereafter employedto ablate cardiac tissue. In this context, preferred embodiments ofablation catheters for use according to the invention are provided withone or more suction ports, allowing the distal portion of the catheterto be adhered to the surface of the epicardium by suction, along withone or more electrodes, located to contact the epicardium of the heartwhen the distal portion of the ablation catheter is secured to theepicardium by suction.

[0008] In additional embodiments of the invention, the catheter orcannula for accessing the pericardial space takes the form of part of animplantable lead system, in which the introducer catheter or cannula isprovided with one or more electrodes adapted to be located in a desiredchamber or chambers of the heart, and wherein an electrode lead ispassed distally through the catheter or cannula into the pericardialspace, to locate additional electrodes adjacent desired portions of theepicardium of the heart. For example, electrodes located within thechamber or chambers of the heart may include pacing, cardioversion ordefibrillation electrodes, and additional such electrodes may be locatedon the lead passing through the catheter or cannula into the pericardialspace.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a plan view of a first embodiment of a catheter orcannula according to the present invention.

[0010]FIG. 2 is a cross-sectional view through the distal portion of thecatheter or cannula of FIG. 1.

[0011]FIG. 3 is a cross-section of the distal portion of the catheter orcannula of FIG. 1, illustrating the extension of a resilient tubularmember located at its distal tip, as the distal tip of the catheter orcannula is passed through the wall of a heart chamber.

[0012]FIG. 4 illustrates the configuration of the distal end of thecatheter of FIGS. 1-3, after proximal movement of the distal tip of thecatheter or cannula results in lateral expansion of the resilienttubular member causing the distal tip of the catheter or cannula to beanchored within the pericardial space.

[0013]FIG. 5 is a cross-section through an alternative embodiment of adistal end portion of a catheter or cannula otherwise as illustrated inFIGS. 1-4.

[0014]FIG. 6 is a cross-sectional view through an additional alternativeembodiment of a catheter or cannula according to the present invention,also employing an extendible flexible tubular member.

[0015]FIG. 7 illustrates the catheter or cannula of FIG. 6, having theelastic tubular member in an extended condition, as it passes throughthe wall of a heart chamber.

[0016]FIG. 8 illustrates the catheter of FIGS. 6 and 7 after proximalmovement of the distal end of the catheter causes lateral expansion ofthe elastic tubular member to anchor the tip of the catheter within thepericardial space.

[0017]FIG. 9 is a plan view of the third embodiment of a catheter orcannula according to the present invention, employing nested inner andouter tubular members.

[0018]FIG. 10 is a cross-sectional view of the catheter or cannula ofFIG. 9.

[0019]FIG. 11 is a side, sectional view through the catheter or cannulaof FIGS. 9 and 10.

[0020]FIG. 12 illustrates placement of the catheter or cannula of FIGS.9-11, such that the distal portion of the inner tubular member extendsthrough the wall of the heart.

[0021]FIG. 13 illustrates the configuration of the cannula or catheterof FIGS. 9-11 after the inner and outer tubular members of the catheteror cannula are moved relative to one another to cause the flangeslocated thereon to engage the inner and outer surfaces of the heart,stabilizing the distal end of the catheter or cannula within thepericardial space.

[0022]FIG. 14 illustrates an alternative embodiment of the distalportion of the catheter in FIGS. 1-11.

[0023]FIG. 15 illustrates a cross-sectional view of an additionalembodiment of a catheter or cannula according to the present invention,employing an internal spring within a distally located elastic tubularmember, illustrating the tubular member in a longitudinally extendedstate as it passes through the wall of a heart chamber.

[0024]FIG. 16 illustrates the catheter or cannula of FIG. 15 aftercontraction of the spring located within the resilient tubular membercauses lateral expansion of the resilient tubular member in thepericardial space, anchoring the distal portion of the catheter orcannula.

[0025] FIGS. 17-20 illustrate various types of catheters and leads whichmay be inserted into the pericardial space via the catheters or cannulasof FIGS. 1-16, discussed above. In particular, FIG. 17 illustrates adrug delivery catheter; FIG. 18 illustrates a pacing/electrogram sensinglead; FIG. 19 illustrates a cardioversion/defibrillation lead; and FIG.20 illustrates an ablation catheter.

[0026]FIG. 21 illustrates a cross-section through the distal end of theablation catheter of FIG. 20. FIG. 22 illustrates the operation of anablation catheter according to FIG. 20 or 21 to ablate heart tissue.

[0027]FIG. 23 illustrates an alternative embodiment of the distalportion of an ablation catheter otherwise as illustrated in FIGS. 20-22.

[0028]FIG. 24 illustrates a cross-section through the distal end of theablation catheter illustrated in FIG. 23.

[0029]FIG. 25 illustrates a delivery catheter or cannula according tothe present invention, having its distal end passing through the rightatrial appendage of a patient's heart and into the pericardial space, inconjunction with a lead or catheter delivered through the introducercatheter or cannula.

[0030]FIG. 26 illustrates the distal portion of an alternativeembodiment of an introducer catheter or cannula according to the presentinvention, carrying one or more electrodes located along its length, inconjunction with an electrode lead delivered through the catheter orcannula into the pericardial space.

[0031]FIG. 27 illustrates the distal portion of an additionalalternative embodiment of an introducer catheter or cannula according tothe present invention, carrying one or more electrodes located along itslength, in conjunction with an electrode lead delivered through thecatheter or cannula into the pericardial space.

[0032]FIG. 28 illustrates the distal portion of an additionalalternative embodiment of an introducer catheter or cannula according tothe present invention, carrying one or more electrodes located along itslength, in conjunction with an electrode lead or other catheterdelivered through the catheter or cannula as it passes through a wall ofa heart chamber into the pericardial space.

[0033]FIG. 29 illustrates the distal portion of an additionalalternative embodiment of an introducer catheter or cannula according tothe present invention, in conjunction with a catheter delivered throughthe catheter or cannula as it passes through a wall of a heart chamberinto the pericardial space.

[0034]FIG. 30 illustrates the distal portion of the introducer catheteror cannula of FIG. 29, as it passes through a wall of a heart chamberinto the pericardial space.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035]FIG. 1 is a plan view of a delivery catheter or cannula accordingto the present invention. The catheter or cannula is provided with anelongated tubular body 10, which is provided with a fitting 20 at itsproximal end which includes first and second fluid fittings 22 and 24,which may take the form of luer lock fittings. Shown entering theproximal end of fluid fitting 24 is a stylet 28, provided with a knob 26located on its proximal portion. The distal tip of stylet 28 exits thedistal tip 32 of the delivery catheter or cannula. The distal tip of thestylet 28 may be rounded or may be beveled or sharpened in order toassist passage of the distal tip 32 of the catheter or cannula throughthe wall of the patient's heart or through the pericardium, into thepericardial space. An elastic tubular member 30 is illustrated locatedat the distal end of the body 10 of the catheter or cannula, and itsoperation in order to anchor the distal end 32 of the catheter orcannula in the pericardial space is discussed in more detail below. Ifthe catheter or cannula is to be used for fluid delivery, an elastictubular plastic liner may be added, located interior to coil 34.

[0036]FIG. 2 shows a catheter or cannula of FIG. 1 in a sectional view.In this view, it can be seen that the tubular lead body 10 carries afirst coil 36, terminating within a circumferential flange 38 located atthe distal end of the catheter or cannula body 10, and a second coil 34extending distally thereto through the circumferential flange 38. Aresilient elastic member 30, for example fabricated of a thin tube ofsilicone rubber, is shown mounted to and extending from the distal endof the catheter or cannula body 10 to a distal tip member 40,illustrated in this view as being a metallic member. Tube 30 isgenerally cylindrical and may be tapered somewhat at its distal end asillustrated. Tube 30 is free of pre-formed corrugations but, asdiscussed below, will exhibit corrugations in use which will serve tostabilize the distal end of the introducer catheter or cannula in thepericardium or the wall of a chamber of a patient's heart. Surroundingthe distal tip member 40 is a plastic tube 32, tapered at its distal endto provide a more atraumatic tip configuration for the catheter orcannula. In the embodiment illustrated, the stylet 28 is provided withan enlarged portion 33 which engages a corresponding internal flange intip member 40. The stylet 28 may be moved distally with respect to thecatheter or cannula to extend the tubular elastic member 30 and theassociated coil 34, causing the elastic tubular member 30 to neck downtightly around coil 34. Longitudinal extension of tubular member 30 mayoccur prior to or after passage of the distal tip of the catheter intothe pericardial space

[0037]FIG. 3 illustrates the catheter or cannula of FIG. 2 with thetubular member 30 stretched elastically to a greater length than asillustrated in FIG. 2 by distal movement of stylet 28. The tubularmember 30 and the distal end of the catheter or cannula extend throughthe wall 100 of the heart chamber into the pericardial space. In thisview the effect of stretching the tubular member 30 to cause it to neckdown to a reduced circumference and into close contact with coil 34 isapparent. The stretching of the tubular member 30 may be done before orafter passage of the tubular member 30 through the wall 100.

[0038]FIG. 4 illustrates the catheter or cannula of FIGS. 1-3, afterremoval of the stylet 28 which in turn allows for the proximal movementof the distal tip of the catheter, in turn causing expansion of theelastic tubular member 30, to anchor the distal tip of the catheter orcannula within the pericardial space. The distal end of the catheter orcannula body 10 defines a shoulder 10 a on one side of the wall theheart, while the elastic member 30 forms one or more laterally extendingcorrugations projection located interior to the wall 100 or thepericardial space. Depending upon the relative dimensions of the heartwall 100 and the tubular member 100 and the relative amount ofextensibility of the tubular member, the number and configuration of theformed corrugations may vary. The lateral expansion of the tubularmember serves to anchor the distal tip of the catheter in thepericardial space. In the embodiment illustrated, it is assumed that theelasticity of coil 34 and tubular member 30 are sufficient to causeproximal movement of a distal tip of the catheter or cannula, oralternatively, that a mechanism is provided for causing proximalmovement of the coil 34, facilitating proximal movement of the tip ofthe catheter or cannula and expansion of the tubular member 40. In suchembodiments, distal movement of the coil 34 may be also employed aloneor in conjunction with distal movement of the stylet to stretch theresilient tubular member 30. In additional alternative embodiments, thestylet may also be employed to cause proximal movement of the tip of thecatheter or cannula, as illustrated in FIG. 5.

[0039]FIG. 5 illustrates an alternative configuration for the distal tipportion of the catheter or cannula illustrated in FIGS. 1-4. In thisembodiment, all identically labeled components correspond to thoseillustrated in FIG. 4, however, in this case, the stylet differs in thatthe expanded portion 33 a of the stylet takes the form of a ball shaped,rather than a cylindrical shaped member, and that the distal tip member40 a is provided with an elastic, generally tubular member 41,configured to elastically engage the ball shaped protrusion 32 a of thestylet 28 a. In a fashion analogous to that illustrated for a ball-tipstylet for causing relative proximal and distal movement of a lead as inU.S. Pat. No. 5,344,439 issued to Otten, and incorporated herein byreference in its entirety, the proximal movement of the stylet may beused to affirmatively cause proximal movement of the tip member 40, upto the limit of allowable proximal motion of the tip, and thereafter,the resiliency of the locking member 41 allows for release of the ballshaped protrusion 32 a, and withdrawal of the stylet 28 a. In thisembodiment, as in the embodiment described above in which a coilsemployed to pull the distal tip of tubular member 34 proximally, theresultant length of the resilient tubular member 30 may actually lessthan its original length, further facilitating formation of corrugationsAfter the catheter or cannula of FIGS. 1-4 or 5 is anchored so that itsdistal tip is stably located in the pericardial space, the lumen definedby the interior of coil 34 and the aperture through tip member 40provide a path by which an additional catheter or electrode lead may bepassed into the pericardial space. For example, an electrode bearingcatheter employed for pacing, electrogram monitoring, cardioversion ordefibrillation, may be located. Alternatively, a simple, tubularcatheter may be passed into the pericardium which will allow for drugdelivery adjacent the localized portion of the heart. As yet, anadditional alternative, the device may be employed directly as a drugdelivery catheter, by means of fluids injected either through fluidcoupling 24 or 22 as illustrated in FIG. 1. As yet an additionalalternative, the device may be used to deliver a cardiac ablation lead,for example corresponding to those in FIGS. 20-24 and discussed in moredetail below.

[0040]FIG. 6 shows the distal portion of an alternative embodiment of adelivery catheter or cannula according to the present invention. In thisembodiment, the body 110 of the device takes the form of a polymerictube of the sort typically employed in the manufacture of guidingcatheters generally, and may be reinforced by means of an embeddedbraid. Internal to tube 110 is a length of hypodermic tubing 114 whichextends back to the proximal end of the device, and is longitudinallymoveable within the lumen of tube 110. An elastic tapered tubular member112 encircles the distal end of tube 110 and the distal end ofhypodermic tube 114 and is adhesively or otherwise bonded to both tubes.In a fashion analogous to that described above in conjunction with thedevice of FIGS. 1-5, distal movement of hypodermic tubing 114 relativeto tube 110 causes elastic member 112 to stretch and to neck down aroundhypodermic tube 114.

[0041]FIG. 7 illustrates the delivery catheter or cannula of FIG. 6 withhypodermic tubing 114 advanced distally out of the distal end of tube110, stretching tubular member 112, causing it to neck down into contactwith hypodermic tubing 114. The device is shown passing through the wall100 of chamber of a patient's heart, such that the distal most portionof a hypodermic tubing 114 and tubular member 112 are located within thepericardial space.

[0042]FIG. 8 shows the device of FIGS. 6 and 7 after the hypodermictubing 114 is moved proximally relative to tube 110, causing elasticmembrane 112 to bunch up forming one or more corrugations inside thepericardial space or in the wall 100 of a chamber of a patient's heart,stabilizing the distal end of the device within the pericardial space.

[0043]FIG. 9 shows an alternative embodiment of a catheter or cannulaaccording to the present invention. In this case, the device bodyincludes two coaxially nested tubes 210 and 212 which are slideablelongitudinally with respect to one another. At the proximal end of tube210 is a fluid fitting 212, coupled to a lumen within tube 210, andwhich as illustrated carries a stylet or guidewire 220, which extendsout of the distal end of tube 210. The distal portion of tube 210carries a conical flange 218, which is preferably manufactured of anelastic material such as silicone rubber and which may optionally bereinforced with radially extending ribs, if desired. The distal end ofouter tube 212 has a corresponding conical flange 216, oppositelydirected from flange 218.

[0044]FIG. 10 is a cross-section through the body of the device of FIG.9. From this view it can be seen that the outer surface of tube 210 isprovided with outwardly directed projections 222, 224 and 226, which arespaced from one another around the circumference of the tube 210, and asillustrated are located displaced approximately 120° from one another.The outer surface of tube 210 is preferably provided with a series ofsuch projections, spaced at regular intervals along a portion of tube210. Corresponding inwardly directed projections 228, 230 and 232 areprovided on the inner surface of tube 212, also spaced approximately120° from one another. As illustrated, in the configuration shown, theprojections of the respective inner and outer tubes 210 and 212 do notengage one another, allowing the tubes to be slid longitudinally.However, if the inner and outer tube are rotated 60° with respect to oneanother, the projections on each of the inner and outer tubes locatethemselves between the projections on the other tube, causing the tubesto be interlocked and preventing further relative longitudinal movementof inner and outer tubes 210 and 212 relative to one another. Thislocking mechanism is employed in conjunction with stabilization of thedevice as discussed below.

[0045]FIG. 11 illustrates the device of FIG. 9 in a sectional view, inwhich the inwardly directed projections 232 of outer tube 212 and theoutwardly projected projections of tube 210 are visible. In thisconfiguration, the tubes are free to slide longitudinally to oneanother. However, by rotating the tubes 60° relative to one another, theoutward projections 222 of tube 210 locate themselves in the recesses224 between the inwardly projected projections 232 of tube 212, and theinwardly directed projections 232 of tube 212 corresponding to locatethemselves in the recesses 236 defined between the outward projections222 of tube 210, preventing further longitudinal movements of tubes 210and 212.

[0046]FIG. 12 illustrates the device of FIGS. 9-11 with its distal endinserted in the wall 100 in the chamber of a patient's heart. The deviceis positioned so that flange 218 of inner tube 210 is located within thepericardial space, while flange 216 of outer tube 212 is locatedinterior to the patient's heart.

[0047]FIG. 13 illustrates the device of FIG. 12 after proximal movementof tube 210 to bring flanges 216 and 218 into contact with the inner andouter surfaces of the wall 100 of the chamber of a patient's heart, alsocausing radial expansion of the flanges as illustrated. At this point,the inner and outer tubes are rotated relative to one another so thatthe inwardly and outwardly directed projections on the outer and innertubes respectively, interlock with one another, preventing furtherlongitudinal movement and stabilizing the distal end of the catheter inthe wall 100 of the patient's heart. Stylet 220 can now be removed, andthe delivery catheter or cannula may be employed to facilitate placementof a lead, catheter or other device in the pericardial space.

[0048]FIG. 14 illustrates an alternative embodiment of a deliverycatheter or cannula generally corresponding to those illustrated inFIGS. 9-13. In this embodiment, however, the flanges 216 a and 218 a areprovided with slits or recesses as illustrated in order to facilitateradial expansion of the flanges. All other elements correspond toidentically labeled elements in FIGS. 9-12.

[0049]FIG. 15 is an additional embodiment of a delivery catheter orcannula, according to the present invention, shown with its distalportion extending through the wall of a patient's heart. Like thedevices of FIGS. 1-5, discussed above, the device is provided with abody which takes the form of a tube 310, reinforced by means of aninternal coil 318. The distal end of the tube 310 serves as a radiallyextending shoulder 310 a, which is located adjacent the inner surface ofthe wall 100 of a patient's heart chamber. An elastic tube 312 extendsdistally from tube 310 to enclose a tip member 314. Spring 320 extendsfrom a cylindrical flange 322 to the tip member 314. As illustrated,elastic tube 312 and spring 320 have been elongated due to distalmovement of stylet 316, which is provided with an outwardly directedshoulder engaging the proximal end of tip member 314.

[0050]FIG. 16 illustrates the device of FIG. 15 after removal of stylet316, allowing spring 320 to retract and cause radial expansion ofelastic tube 312 within the pericardial space, stabilizing the distalend of the delivery catheter. All other elements correspond toidentically labeled elements in FIG. 15.

[0051] FIGS. 17-24 illustrate various types of devices which may beintroduced into the pericardial space using the delivery devicesillustrated above. In each case, the delivery device is sized so thatthe lumen through the distal tip member of the delivery device isadequate to permit passage of the lead or cannula to be delivered to thepericardial space.

[0052]FIG. 17 illustrates a simple catheter for delivery of drugs or forwithdrawal of pericardial fluid. The catheter consists of a tube 500provided with a fluid fitting 502 at its proximal end.

[0053]FIG. 18 illustrates an electrode lead with may be introducedthrough any of the delivery devices described above, and which may beemployed for detection of electrical signals from the heart or deliveryof electrical stimulus pulses such as pacing pulses to the heart. Thelead is provided with an elongated insulative body 504 which carries twomutually insulative conductors therein coupled at their distal ends toelectrodes 500 and 508, respectively, and at their proximal end toconnector pin and connector ring 514 and 512, respectively. Connectorpin 514 and connector ring 512 are located on a connector assembly 510which is adapted to be inserted into the connector port of an associatedelectrical stimulator or monitor.

[0054]FIG. 19 illustrates a cardioversion or defibrillation lead whichmay be introduced by means of any of the delivery devices describedabove. The lead is provided with an elongated insulative lead body 516which carries an elongated conductor coupled at its distal end to coilelectrode 518 and at its proximal end to connector pin 522. Connectorpin 522 is located on a connector assembly 520 adapted to be coupled toa cardioverter or defibrillator.

[0055]FIG. 20 illustrates an ablation catheter which may be employed inconjunction with any of the delivery devices illustrated above. Theablation catheter is provided with an elongated lead body 524 which isprovided with a longitudinally extending internal lumen extending from afluid coupling 528 at its proximal end to a longitudinally extendingrecess 536 at its distal end. Fluid coupling 528 is mounted to fitting526, which also carries two electrical connectors 530, which are coupledto the distal ends of conductors 531, which extend through catheter body524 to electrodes which are located within the recess 536, but which arenot visible in this view. The distal portion 532 of the device is alsoprovided with two laterally extending flanges 534, which serve to orientthe device such that the recess 536 is located adjacent the surface ofthe heart tissue, as illustrated in FIGS. 21 and 22, described below.

[0056]FIG. 21 is a cross-sectional view of the distal portion 532 of thedevice illustrated in FIG. 20. In this view it can be seen that thedistal portion of the catheter has a portion which is generally U-shapedin cross section, defining recess 536, and carries two elongated stripelectrodes 542 and 544 located on opposite sides within recess 536.Laterally extending flanges 534 are located adjacent recess 536 andserve to assure that the recess is oriented with its open portionadjacent heart tissue. Also visible is a lumen 538 which serves tocouple the recess 536 to the fluid coupling 528 (FIG. 20) located at theproximal end of the lead. An optional tension wire 540 is shown whichmay, in some embodiments, be employed to cause deflection of thecatheter, in order to facilitate its placement at a desired location onthe epicardial surface of the patient's heart, using a mechanism asgenerally disclosed in U.S. Pat. No. 5,489,270, issued to Van Erp,incorporated herein by reference in its entirety.

[0057]FIG. 22 illustrates the ablation catheter of FIGS. 20 and 21applied to the epicardial surface of a wall 600 of a chamber of thepatient's heart. Application of vacuum to the fluid fitting 528 (FIG.20) located at the proximal portion of the catheter causes the wall 600of the chamber of the patient's heart to be drawn into the recess 536,between electrodes 542 and 544. RF energy can then be applied toelectrodes 542 and 544 via conductors 531 to create a linear lesion,extending along the length of electrodes 542 and 544.

[0058]FIG. 23 illustrates an alternate embodiment of the distal portionof an ablation catheter otherwise corresponding to the catheterillustrated in FIGS. 21-22. In this case, it should be understood thatthe proximal portion of the catheter corresponds to that illustrated inFIG. 20, with catheter body 610 corresponding to catheter body 524 inFIG. 20. The distal portion of the catheter is provided with laterallyextending flanges 612, corresponding generally to flanges 534. However,rather than being provided with an elongated recess, the device isprovided with a longitudinal series of recesses 614. The device is alsoprovided with two longitudinally extending electrodes 618 and 620 whichmay take the form of metal strips or coils, located on either side ofrecesses 614. Electrode 618 and 612 are coupled to electrical connectorsat the proximal end of the lead, corresponding to electrical connectors530 in FIG. 20.

[0059]FIG. 24 illustrates a cross-section through the distal portion ofthe ablation catheter illustrated in FIG. 23. In this view it can beseen that the recesses 614 are generally conical, and are in fluidcommunication with an internal lumen 624 which extends back to a fluidcoupling at the proximal end of the catheter, corresponding to fluidcoupling 528 in FIG. 20. Electrodes 618 and 620 are illustrated incross-section, located on either side of recesses 614. An optionaltension wire 626 is shown, which may be employed to deflect the ablationcatheter assisting its location at a desired location on the epicardiumof a patient's heart. In use, like the ablation catheter of FIGS. 20-22,vacuum is applied to the fluid coupling at the proximal end of thecatheter, causing the suction ports 614 to adhere to the epicardialsurface of a chamber of the patient's heart. RF energy is appliedbetween electrodes 618 and 620 to create a generally linear lesion.

[0060]FIG. 24 illustrates the use of a delivery device according to thepresent invention to deliver a lead or catheter 420 into the pericardialspace. As illustrated, it should be assumed that the delivery devicecorresponds to that illustrated in FIGS. 1-4, with lead body 10extending from the superior vena cava, the distal end of the deliverydevice extending through the wall 400 of the right atrial appendage. Asillustrated, elastic tube 20 serves to stabilize the distal end of thedelivery device in the right atrial appendage and lead or catheter 420is delivered through the distal tip of the delivery device, for locationbetween the epicardial surface of the heart and the pericardium,illustrated schematically at 410.

[0061] Any of the delivery devices illustrated above may be employed ina corresponding fashion to deliver a lead or catheter to the pericardialspace, or may be used in the absence of an associated lead or catheterto deliver materials such as drugs or genetic agents to the pericardialspace or to withdraw fluid from the pericardial space. Correspondingly,devices according to any of the embodiments illustrated above may alsobe employed to access pericardial space by passing through thepericardium itself, with the distal end of the catheter stabilized inthe pericardium, rather than in the wall of the chamber of a patient'sheart.

[0062]FIG. 26 illustrates an additional embodiment of a delivery deviceaccording to the present invention, wherein the delivery device isprovided with an electrode 708 located at the distal portion of the tube710, making up the catheter body. Catheter body 710 may otherwisecorrespond to catheter body 10 of the device illustrated in FIGS. 1-4.As illustrated, the device is shown with its distal end extendingthrough the wall 100 of a chamber of a patient's heart, for example,extending through the right atrial appendage. Elastic tube 712 maycorrespond to tube 30, illustrated in FIG. 1, serving to anchor thedevice in the wall of the atrium in the same fashion as described inconjunction with FIGS. 1-4, above. Extending into the pericardial spaceis an electrode lead 714, in this case taking the form of adefibrillation lead with an elongated coil electrode 17. In anembodiment as illustrated, electrode 708 may be employed to sense orpace the atrium or other chamber of a patient's heart, with electrode 17employed in conjunction with cardioversion or defibrillation functions.Alternatively, a lead carrying pacing and/or electrogram sensingelectrodes may be substituted for lead 714, or lead 714 may be omitted,and the device simply employed to deliver drugs to the pericardial spacein conjunction with pacing or monitoring the electrical activity of thepatient's heart via electrode 708.

[0063]FIG. 27 illustrates an additional alternative embodiment to adevice generally corresponding to that illustrated in FIG. 26. In thiscase, the device is provided with an electrode 724 located on alaterally extending arm 726 in addition to ring electrode 709 to contactthe wall 100 of a chamber of a patient's heart. Catheter body 720 maycorrespond to the catheter body 10, as illustrated in FIGS. 1-4 above,and is stabilized in the wall 100 of a chamber of the patients heart byelastic tube 722 which also may correspond to elastic tube 30 in FIGS.1-4. In this case, an electrode lead 228 which carries pacing/sensingelectrodes 730 and 732 is shown extending into the pericardial space. Asin conjunction with the device illustrated in FIG. 26, lead 728 may bereplaced by a cardioversion/defibrillation lead, an ablation catheter,or may be omitted entirely.

[0064]FIG. 28 illustrates an additional alternative embodiment of adelivery catheter or cannula 740, which is provided with a helicalfixation member 746 which might also function as an electrode. Helicalfixation 746 may be coupled to a coiled conductor 742 within the body ofthe cannula 740 by means of a conductive sleeve 750 as illustrated. Inalternative embodiments, the helix 746 may merely serve to anchor thecatheter or cannula 740 adjacent the wall 100 of the heart chamber. Thecatheter or cannula 740 is provided with a molded polymer seal 748through which a catheter, guidewire, or electrode lead 744 passes. Seal748 serves to seal the distal end of the delivery catheter or cannula740 from fluid intrusion.

[0065] In cases in which the helix 746 is coupled to an internalconductor within the delivery catheter or cannula 740 and is intended tobe used as an electrode, it may be used, for example, to stimulate theright atrium of the heart, with the electrode lead 744 extendingtherethrough passing into the pericardial space and around the heartinto contact with another chamber of the heart, such as the left atriumor left ventricle of the heart.

[0066]FIG. 29 illustrates an additional alternative embodiment of adelivery catheter or cannula according to the present invention. Thedelivery catheter or cannula comprises an outer tubular sheath 800mounted concentrically around an inner tubular sheath 806. The outertubular sheath 800 is provided with a series of longitudinal slots 802which separate the outer sheath into parallel ribs which, as illustratedin FIG. 30 below, may be deflected outward to provide a mechanism foranchoring a delivery catheter or cannula adjacent one surface of a wallof a heart chamber. Inner catheter or cannula 806 is provided with arearward facing generally conical resilient flange 808, correspondinggenerally to the flange 218 on the introducer catheter or cannula ofFIG. 9. Inner tubular member 806 may be displaced longitudinallyrelative to outer tubular member 800 by means of associated handles 810and 804. Located within inner tubular sheath 806 is a fluid deliverycatheter 812, which extends out the distal end of inner tubular member806 and is slidable longitudinally with regard to inner tubular member806. Fluid delivery catheter 812 also has a handle 814 on its proximalend and is provided with a luer fitting 816 allowing for connection to afluid source.

[0067]FIG. 30 illustrates the configuration of the delivery catheter orcannula of FIG. 29 as it passes through the wall 100 of a chamber of theheart. The catheter or cannula is anchored to the wall 100 of the heartby first passing the conical flange 804 of the inner tubular member 806through the wall of the heart, thereafter advancing the outer tubularmember distally until its distal end engages the wall of the heart, andthen advancing the tubular member further distally, causing lateralexpansion of the ribs 803 as illustrated to anchor the catheter. Tubulardelivery catheter 812 may then be advanced distally the distal end ofthe inner tubular member 806, exposing laterally oriented delivery ports820, which ports were previously located within and sealed by a distalportion of the inner tubular member 806.

[0068] While the present invention is directed primarily toward accessto the pericardial space, it is believed that the devices illustratedand describe herein may also usefully be employed to access otherportions of the body, particularly spaces within or between other bodyorgans and more particularly to spaces which need to be accessed bypenetrating a layer or wall of body tissue. As such, it should beunderstood that the devices which are the subject of the followingclaims are not necessarily limited in use to pericardial access.

[0069] In conjunction with the above specification, we claim:

1. An apparatus for delivering a medical device to a desired locationwithin a patient's body; comprising: an elongated device body having aproximal end and a distal end and having an internal, longitudinallyextending lumen open to the distal end of the device body; and astabilizing mechanism located at the distal end of the device body, thestabilizing mechanism in turn comprising: a tubular elastic memberhaving a proximal end attached to the device body and having firstlength and a first outer circumference in a first configuration; meansfor causing the tubular member to change from the first configuration toa second configuration by elastically stretching the tubular elasticmember longitudinally to a second length greater than the first lengthand thereby causing the tubular member to neck down to a second diametersmaller than the first diameter; and means for causing the tubularelastic member to change from the second configuration to a thirdconfiguration having a third length less than the second length and athird circumference greater than the second circumference.
 2. Anapparatus according to claim 1, wherein the tubular elastic membercomprises a non-corrugated tubular member wherein the means for causingthe tubular member to change from the second configuration to a thirdconfiguration comprises means for causing the tubular member to changefrom the second configuration to a third configuration having at leastone corrugation which has the third outer circumference.
 3. An apparatusaccording to claims 1 or claim 2, wherein the means for causing thetubular member to change from the second configuration to a thirdconfiguration comprises means for causing the tubular member to changefrom the second configuration to a third configuration wherein the thirdlength is less than the first length.
 4. An apparatus according to claim1 or claim 2 wherein the tubular elastic member comprises a generallycylindrical tubular member.
 5. An apparatus according to claim 1 orclaim 2 wherein the tubular elastic member tapers distally.
 6. Anapparatus according to claim 1 or claim 2 wherein the means for causingthe tubular member to change from the first configuration to a secondconfiguration comprises a longitudinally movable tubular member withinthe device body, coupled to a distal portion of the elastic tubularmember.
 7. An apparatus according to claim 1 or claim 2 wherein themeans for causing the tubular member to change from the firstconfiguration to a second configuration comprises a longitudinallymovable solid member within the device body, coupled to a distal portionof the elastic tubular member.
 8. An apparatus according to claim 1 orclaim 2 wherein the means for causing the tubular member to change fromthe first configuration to a second configuration comprises alongitudinally movable stylet engaging the distal portion of the elastictubular member.
 9. An apparatus according to claim 1 or claim 2 whereinthe means for causing the tubular member to change from the firstconfiguration to a second configuration comprises a longitudinallymovable coil engaging the distal portion of the elastic tubular member.10. An apparatus according to claim 1 or claim 2 wherein the means forcausing the tubular member to change from the second configuration to athird configuration comprises the resiliency of the tubular member. 11.An apparatus according to claim 1 or claim 2 wherein the means forcausing the tubular member to change from the second configuration to athird configuration comprises a coil extending through the resilienttubular member.
 12. An apparatus according to claim 1 or claim 2 whereinthe means for causing the tubular member to change from the secondconfiguration to a third configuration comprises a spring coil extendingthrough the resilient tubular member.
 13. An apparatus according toclaim 1 or claim 2 wherein the means for causing the tubular member tochange from the second configuration to a third configuration comprisesa longitudinally movable tubular member within the device body, coupledto a distal portion of the elastic tubular member.
 14. An apparatusaccording to claim 1 or claim 2 wherein the means for causing thetubular member to change from the second configuration to a thirdconfiguration comprises a longitudinally movable coil within the devicebody, coupled to a distal portion of the elastic tubular member.
 15. Anapparatus according to claim 1 or claim 2 wherein the means for causingthe tubular member to change from the second configuration to a thirdconfiguration comprises a longitudinally movable solid member within thedevice body, coupled to a distal portion of the elastic tubular member.16. An apparatus according to claim 1 or claim 2 wherein the means forcausing the tubular member to change from the second configuration to athird configuration comprises a longitudinally movable stylet within thedevice body, coupled to a distal portion of the elastic tubular member.17. An apparatus for delivering a medical device to a desired locationwithin a patient's body; comprising: an outer tube having proximal anddistal ends and provided with at least one inwardly directed projectionand having a radially extending first flange adjacent its distal end;and an inner tube located within and longitudinally movable within theouter tube and having proximal and distal ends and having a radiallyextending second flange adjacent its distal end, located distal to thedistal end of the outer tube and provided with at least one inwardlydirected projection engageable with the inwardly directed projection ofthe outer tube and having a radially extending second flange adjacentits distal end, located distal to the distal end of the outer tube;wherein: at least one of the inner and outer tubes are provided with aplurality of longitudinally spaced projections such the inwardly andoutwardly directed projections may engage one another at multiplelocations.
 18. An apparatus according to claim 17 wherein the inner andouter tubes are rotatable relative to one another such that the tubesmay be rotated between a first position in which the inwardly andoutwardly directed projections are aligned and interlock and a secondposition in which the projections are angularly displaced from oneanother and the first and second tubes are longitudinally movable withrespect to one another.
 19. An apparatus according to claim 17 or claim18 wherein first and second flanges extend longitudinally betweenproximal and distal ends and wherein the second flange is a resilient,generally conical flange having its largest diameter adjacent its distalend and wherein the first flange is a resilient, generally conicalflange having its largest diameter adjacent its proximal end.
 20. Anablation catheter, comprising: a catheter body having proximal anddistal ends and having a longitudinally extending internal lumen andcarrying an elongated conductor therein; a catheter head located atdistal portion of the catheter body, the catheter head provided with alongitudinally extending recess in fluid communication with the lumen ofthe lead body and having flanges extending laterally from the recess;and an electrode coupled to the conductor within the lead body andextending along the recess.
 21. An ablation catheter according to claim20, wherein the electrode is located within the recess.
 22. An ablationcatheter, comprising: a catheter body having proximal and distal endsand having a longitudinally extending internal lumen and carrying anelongated conductor therein; a catheter head located at distal portionof the catheter body, the catheter head provided with a longitudinallyextending series of recesses in fluid communication with the lumen ofthe lead body and having flanges extending laterally from the recess;and an electrode coupled to the conductor within the lead body andextending along the series of recesses.
 23. An ablation catheteraccording to claim 22, wherein the electrode is located alongside therecess.
 24. An ablation catheter, comprising: a catheter body havingproximal and distal ends and having a longitudinally extending internallumen and carrying an elongated conductor therein; a catheter headlocated at distal portion of the catheter body, the catheter headprovided with a recess in fluid communication with the lumen of the leadbody and having flanges extending laterally from the recess; and anelectrode coupled to the conductor within the lead body and extendingalongside the recess.
 25. An ablation catheter, comprising: a catheterbody having proximal and distal ends and having a longitudinallyextending internal lumen and carrying an elongated conductor therein; acatheter head located at distal portion of the catheter body, thecatheter head provided with a recess in fluid communication with thelumen of the lead body and having flanges extending laterally from therecess; and an electrode coupled to the conductor within the lead bodyand located within the recess.
 26. A method of accessing a desiredlocation within a patient's body; comprising: advancing to tissueadjacent the desired location a device comprising an elongated devicebody having a proximal end and a distal end and having an internal,longitudinally extending lumen open to the distal end of the devicebody, and a stabilizing mechanism located at the distal end of thedevice body, the stabilizing mechanism in turn comprising a tubularelastic member having a proximal end attached to the device body andhaving first length and a first outer circumference; passing the tubularmember through the body tissue to reach the desired site and causing thetubular member to change from the first configuration to a secondconfiguration by elastically stretching the tubular elastic memberlongitudinally to a second length greater than the first length andthereby causing the tubular member to neck down to a second diametersmaller than the first diameter; and thereafter causing the tubularelastic member to change from the second configuration to a thirdconfiguration having a third length less than the second length and athird circumference greater than the second circumference to anchor thedevice body to the body tissue.
 27. A method according to claim 26,wherein advancing the catheter comprises advancing a catheter whereinthe tubular elastic member comprises a non-corrugated tubular memberwherein causing the tubular member to change from the secondconfiguration to a third configuration comprises causing the tubularmember to have at least one corrugation which has the third outercircumference.
 28. A method according to claim 26 or claim 27, causingthe tubular member to change from the second configuration to a thirdconfiguration comprises causing the tubular member to have a thirdlength less than the first length.
 29. A method according to claim 26 orclaim 27 wherein advancing the catheter comprises advancing a devicehaving a tubular elastic member which comprises a generally cylindricaltubular member.
 30. An apparatus according to claim 26 or claim 27advancing the catheter comprises advancing a device having a tubularelastic member which tapers distally.
 31. A method of accessing adesired location within a patient's body; comprising advancing to tissueadjacent the desired location a device comprising an outer tube havingproximal and distal ends and provided with at least one inwardlydirected projection and having a radially extending first flangeadjacent its distal end and an inner tube located within andlongitudinally movable within the outer tube and having proximal anddistal ends and having a radially extending second flange adjacent itsdistal end, located distal to the distal end of the outer tube andprovided with at least one inwardly directed projection engageable withthe inwardly directed projection of the outer tube and having a radiallyextending second flange adjacent its distal end, located distal to thedistal end of the outer tube, wherein at least one of the inner andouter tubes are provided with a plurality of longitudinally spacedprojections such the inwardly and outwardly directed projections mayengage one another at multiple locations; passing the distal portion ofthe inner tube and the second flange through the body tissue to thedesired site and longitudinally moving the outer tube distally relativeto the inner tube and engaging the inwardly and outwardly projectionswith one another to stabilize the device in the body tissue.
 32. Amethod according to claim 31, wherein: advancing the device comprisesadvancing a device wherein the inner and outer tubes are rotatablerelative to one another such that the outer tube may be rotated relativeto the inner tube between a first position relative to the inner tube inwhich the inwardly and outwardly directed projections are aligned andinterlock and a second position relative to the inner tube in which theprojections are angularly displaced from one another and the first andsecond tubes are longitudinally movable with respect to one another;wherein longitudinally moving the outer tube distally relative to theinner tube comprises moving the outer tube while in the first positionrelative to the inner tube; and wherein engaging the inwardly andoutwardly projections with one another comprises rotating the outer tubeto the second position relative to the inner tube.
 33. A methodaccording to claim 31 or claim 32 wherein advancing the device comprisesadvancing a device wherein the first and second flanges extendlongitudinally between proximal and distal ends and wherein the secondflange is a resilient, generally conical flange having its largestdiameter adjacent its distal end and wherein the first flange is aresilient, generally conical flange having its largest diameter adjacentits proximal end.
 34. A method of ablation, comprising: advancing to adesired site an ablation catheter comprising a catheter body havingproximal and distal ends and having a longitudinally extending internallumen and carrying an elongated conductor therein; a catheter headlocated at distal portion of the catheter body, the catheter headprovided with a longitudinally extending recess in fluid communicationwith the lumen of the lead body and having flanges extending laterallyfrom the recess; and an electrode coupled to the conductor within thelead body and extending along the recess; applying suction to the lumenwithin the lead body to draw the tissue into the recess and into contactwith the electrode; and applying RF energy to the conductor.
 35. Amethod of ablation, comprising: advancing to a desired site an ablationcatheter comprising a catheter body having proximal and distal ends andhaving a longitudinally extending internal lumen and carrying anelongated conductor therein; a catheter head located at distal portionof the catheter body, the catheter head provided with a longitudinallyextending series of recesses in fluid communication with the lumen ofthe lead body and having flanges extending laterally from the recess;and an electrode coupled to the conductor within the lead body andextending along the series of recesses; applying suction to the lumenwithin the lead body to draw the tissue against the recesses and intocontact with the electrode; and applying RF energy to the conductor. 36.A method of ablation, comprising: advancing to a desired site anablation catheter comprising a catheter body having proximal and distalends and having a longitudinally extending internal lumen and carryingan elongated conductor therein; a catheter head located at distalportion of the catheter body, the catheter head provided with a recessin fluid communication with the lumen of the lead body and havingflanges extending laterally from the recess; and an electrode coupled tothe conductor within the lead body and extending alongside the recess;applying suction to the lumen within the lead body to draw the tissueagainst the recesses and into contact with the electrode; and applyingRF energy to the conductor.
 37. A method of ablation, comprising:advancing to a desired site an ablation catheter comprising a catheterbody having proximal and distal ends and having a longitudinallyextending internal lumen and carrying an elongated conductor therein; acatheter head located at distal portion of the catheter body, thecatheter head provided with a recess in fluid communication with thelumen of the lead body and having flanges extending laterally from therecess; and an electrode coupled to the conductor within the lead bodyand located within the recess; applying suction to the lumen within thelead body to draw the tissue into the recess and into contact with theelectrode; and applying RF energy to the conductor.
 38. An apparatus foraccessing a desired location within a patient's body; comprising: atubular body having an internal lumen therein, having proximal anddistal ends and provided with a helical fixation member extending fromthe distal end and a resilient seal sealing the lumen at the distal endof the tubular body, and an elongated member passing through the lumen,through the resilient seal and through the helical fixation member. 39.An apparatus for delivering fluid to a desired location within apatient's body; comprising: an outer tubular body having an internallumen therein, having proximal and distal ends and provided with alaterally extending portion adjacent its distal end; an inner tubularmember slidably located within the outer tubular member, having proximaland distal ends and provided with a laterally extending portion adjacentits distal end; and a fluid delivery catheter slidably located in theinner tubular member, having proximal and distal ends and provided withlaterally directed fluid delivery ports adjacent its distal end, thedistal end of the fluid delivery catheter being locatable within theinner tubular member.
 40. An apparatus for delivering fluid to a desiredlocation within a patient's body; comprising: a tubular member, havingproximal and distal ends and provided with a means adjacent its distalend for stabilizing the tubular member relative to body tissue throughwhich the tubular member may extend; and a fluid delivery catheterslidably located in the tubular member, having proximal and distal endsand provided with laterally directed fluid delivery ports adjacent itsdistal end, the distal end of the fluid delivery catheter beinglocatable within the tubular member.